An Update

©2010 JCO, Inc. May not be distributed without permission. www.jco-online.com
The Space-Closure Alternative for
Missing Maxillary Lateral Incisors:
An Update
MARCO ROSA, MD, DDS, DO
BJÖRN U. ZACHRISSON, DDS, MSD, PHD
T
reatment planning for patients with missing
maxillary lateral incisors traditionally includes
either space closure1,2 or space reopening and
insertion of implants.2,3 Some common objections
to orthodontic space closure are that the treatment
outcome may not look “natural”, that the functional occlusion is compromised, and that retention
of the treatment result is difficult.
Although it may appear preferable esthetically and functionally to create space for replacement of the missing lateral incisor with a
single-tooth implant4,5 or resin-bonded bridge,6 and
while high survival rates for implant-supported
porcelain crowns can be expected, long-term biological complications are frequent7-19 (Table 1). At
present, it is not possible to predict when such
unesthetic changes will appear. Progressive infra­
occlusion may occur due to the continuous erup-
tion of adjacent teeth (Fig. 1), even when an
implant is placed in a mature adult.8,9,13-15 Obviously,
an osseointegrated implant crown will not undergo
the normal uprighting of upper and lower incisors
that occurs from adolescence to adulthood,16,17
which means the implant crown will become more
infraoccluded and protrusive in appearance over
time.13 Furthermore, blue coloring of the labial
gingiva has been reported above more than 50%
of single-implant crowns at four-year follow-ups.12
Such darkening is caused by the resorption of
endosteally derived bone, which is more porous
and more prone to resorption than periosteal bone.
Abutment exposure due to retraction of the labial
gingiva is another complication,13 possibly caused
by toothbrushing damage and other factors. The
frequent lack of complete gingival papillary fill
around implant crowns12,18 may also have esthetic
TABLE 1
ADVANTAGES AND COMPLICATIONS OF IMPLANT SUBSTITUTION FOR
MISSING MAXILLARY LATERAL INCISORS
Advantages of Single Implants
Common Complications of Single Implants
• Optimal posterior occlusion • Progressive infraocclusion (even in mature adults)
• Satisfactory short-term esthetics
• Lack of uprighting compared to natural incisors
• Comparatively short and simple
orthodontic treatment
• No means of orthodontic adjustment
• No need for build-ups of neighboring teeth
• Blue coloring of labial gingiva
• Visibility of metal or porcelain abutment over time
• Long-term implant osseointegration
• Interdental recession (particularly distal papilla)
• Difficulty of making natural-looking porcelain crown
• No long-term observations (>10-15 years)
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© 2010 JCO, Inc.
JCO/SEPTEMBER 2010
Dr. Rosa is a Professor of Orthodontics, Insubria University, Varese,
Italy, and in the private practice of orthodontics at Piazza della
Mostra, 19, 38122 Trento, Italy; e-mail: [email protected]. Dr.
Zachrisson is an Associate Editor of the Journal of Clinical Ortho­
dontics; a Professor Emeritus, Department of Orthodontics,
University of Oslo, Norway; and in the private practice of orthodontics in Oslo.
Dr. Rosa
consequences. Finally, it should be remarked that
it is not easy to make implant crowns that blend
perfectly with the neighboring teeth. Indeed,
Tuverson remarked that the color of the canine
usually comes closer to that of adjacent teeth than
to the color of porcelain crowns.19
Our appreciation of the space-closure alternative has increased during the last decade as we
have tried to improve our results by combining
carefully detailed orthodontic treatment with techniques from esthetic dentistry20,21 (Fig. 2). Used
A
B
Dr. Zachrisson
together, these methods can provide the improvements needed to approach the appearance of a
natural intact dentition and thus make orthodontic
space closure a more attractive treatment alternative, especially in young patients and in those who
show a substantial amount of gingiva when smiling. A biological, esthetic, and stable result using
natural teeth in the anterior maxilla appears more
appealing to us than the insertion of foreign bodies
that will remain in place throughout the patient’s
lifetime.
C
Fig. 1 A. 20-year-old female patient with upper lateral incisor space reopened for implant placement. B. Temporary crown on implant looks ideal at end of orthodontic treatment. C. Only five years later, infraocclusion of implant restoration is evident due to continuous eruption of adjacent teeth.
A
B
C
Fig. 2 A. Adolescent female patient with maxillary right lateral incisor agenesis and peg-shaped left lateral
incisor (same case as shown in Figure 4 of previous article20). B. Right canine extruded during orthodontic
space-closure treatment and recontoured solely by grinding; porcelain laminate veneer crown placed over
peg-shaped lateral. C. Natural gingival and incisal contours maintained 19 years after treatment, with no
sign of infraocclusion; gingivae show normal pink color, stippling, and intact interdental papillae.
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The Space-Closure Alternative for Missing Maxillary Lateral Incisors
We have also recommended that clinicians
should evaluate and eventually restore the central
incisors in many patients with missing lateral incisors.21 Widening and lengthening the central incisors allows such patients to optimally display their
dentition during speech and smiling.
We have achieved satisfactory, stable outcomes over many years of using canine substitution for missing lateral incisors.20,21 In some pa­­-
tients, however, the resulting dentitions did not
appear entirely natural; in others, the composite
resin build-ups20 needed more maintenance than
expected. In this article, we have selected two difficult and challenging patients from Dr. Rosa’s
pool of recently treated maxillary lateral agenesis
cases to demonstrate further improvements and
provide new clinical guidelines for the spaceclosure alternative.
A
Fig. 3 Case 1. A. 17-year-old female patient after previous orthodontic
treatment to open maxillary lateral spaces for dental implants. Occlusion
appears normal, but upper incisors were protruded in attempt to correct overjet, profile, and Class III skeletal tendency. B. Lateral incisors
temporarily replaced on removable plate.
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B
JCO/SEPTEMBER 2010
Rosa and Zachrisson
Case 1
A 17-year-old female presented with a Class
I malocclusion and a hypodivergent Class III skeletal tendency due to a retrognathic, short maxilla
(Fig. 3). The mandibular arch was normally
shaped, with minor crowding. Because of the Class
III malocclusion and narrow maxilla, a previous
orthodontist had decided to open space and
improve the profile by means of maxillary expansion and upper incisor proclination. The patient
was awaiting implant substitution “at the end of
growth”, but was not fully satisfied with the interim result.
Our advice was not to refine the initial treatment, but to start over with different goals:
• Space closure and retraction of the upper in­­
cisors.
• Surgical maxillary advancement, involving vertical augmentation with clockwise rotation of the
occlusal plane, to increase the amount of maxillary
incisor display in smiling and the overall vertical
dimension of the face.
• Cosmetic and functional composite restoration
of the six anterior teeth at the end of orthodontic
treatment.
• Porcelain laminate veneers to replace the composite restorations at the end of growth.
We believed such a treatment approach could
achieve not only an optimal occlusion, but a wellbalanced, natural smile that would be stable over
the long term.
At the beginning of orthodontic treatment,
the upper canines were reshaped mesiodistally
by stripping, and their buccal surfaces were flattened. Maxillary space closure was obtained in six
months using fixed appliances supported by Class
II elastics (Fig. 4). It is of considerable interest that
after the space closure, the profile did not worsen
from a clinical point of view, despite the 7mm
retraction of the upper incisors. On the other hand,
it is not likely that a significant improvement in
the profile could have been achieved by moving
the teeth in the opposite direction (by proclining
the upper incisors), considering the narrow, retro­
gnathic maxilla of this hypodivergent patient.
A maxillary vertical augmentation with
mesial displacement and rotation of the palatal and
occlusal planes was performed by Dr. Mirco
Raffaini, Parma, Italy. The lower third molars
were extracted during the surgery.
Orthodontic finishing lasted 11 months. Mod­
­erate stripping was performed on the lower anterior teeth during this stage. The gingival shape and
contour and the smile line were corrected by premolar intrusion and canine extrusion with torque
Fig. 4 Case 1. Patient after six
months of maxillary space closure.
Maxillary incisors were uprighted
and retracted 7mm, resulting in
anterior crossbite; first premolars
were intruded to produce normal
high-low-high gingival contour.
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The Space-Closure Alternative for Missing Maxillary Lateral Incisors
A
A
Fig. 5 Case 1. A. Patient after 11 months of orthodontic finishing. B. Superimposition of pre- and post-treatment cephalometric tracings.
B
control20,21 (Fig. 5A). The marked improvement in
facial esthetics was obtained mainly by an increase
in the vertical dimension at the maxillary level and
concomitant mandibular rotation, rather than sagittal modifications, while the position of the upper
lip in the face was unchanged (Fig. 5B).
The cosmetic phase (performed by Dr.
Patrizia Lucchi, Trento, Italy) began on the day of
debonding. The upper six anterior teeth were re­­
built with composite resin to obtain an ideal toothto-tooth and tooth-to-soft-tissue relationship (Fig.
6A). Vital bleaching was performed after the composite build-ups to match the yellowish canine to
the white composite (Fig. 6B); the resin build-ups
will later be replaced by porcelain laminate
veneers. The final occlusion showed the first
molars in a Class II relationship, with canines
substituting for the missing lateral incisors and
first premolars replacing the canines (Fig. 6C).
The smile line and upper incisor display with the
lips at rest were ideal for a woman of this age.
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Retention consisted of a maxillary six-unit
lingual retainer (4-3-1-1-3-4, with the distal ends
bonded to the mesial occlusal surfaces of the first
premolars) and a mandibular 3-3 lingual retainer.
Case 2
A 34-year-old male presented with a Class
II, division 2 malocclusion in a hypodivergent
skeletal pattern (Fig. 7). Both maxillary lateral
incisors were missing. The upper left deciduous
canine was retained, but was severely resorbed and
splinted to the adjacent permanent canine and first
premolar. The upper right and lower left first
molars were also missing. A marked asymmetry
of the dental arches and the occlusal plane made
the patient’s gummy smile more evident on the
right side.
Considering the gummy smile and the relatively young age of the patient, we felt the placement of two implants in the esthetic zone would
JCO/SEPTEMBER 2010
Rosa and Zachrisson
A
B
B
C
Fig. 6 Case 1. A. Composite restorations of central incisors and relocated canines and first premolars. B. After vital bleaching of relocated canines. C. Final result, with maxillary molars in Class II relationship
and six anterior teeth rebuilt with composite resin to produce optimal tooth-to-tooth and tooth-to-soft-tissue
relationships. Incisor display with lips at rest is ideal for young adult woman. Upper and lower six-unit retainers were bonded; resin build-ups will eventually be replaced by porcelain laminate veneers.
be an unsatisfactory long-term solution. Therefore,
the treatment plan involved:
• Space closure to replace the upper left deciduous
canine and correct the midline.
• Space opening between the upper right first and
second premolars to allow insertion of an implant
that would expedite the midline correction.
• Closure of the upper right first molar space.
• Leveling and alignment (with stripping in the
VOLUME XLIV NUMBER 9
anterior region) and correction of root angulation
on the lower left side, without reopening the space
of the missing lower left first molar.
• Correction of the asymmetrical occlusal plane.
• Achievement of a functional, balanced occlusion
with canine and incisal guidance through ortho­
dontic treatment and restorations.
• Porcelain crown restoration over the first premolar implant.
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Fig. 7 Case 2. 34-year-old male patient with Class II, division 2 malocclusion, midline deviation, missing upper lateral incisors, and maxillary
asymmetry due to missing upper right and lower left first molars.
Retained upper left deciduous canine had been splinted to adjacent
permanent canine and first premolar.
A
B
Fig. 8 Case 2. A. Patient after 18 months of treatment, showing diastemas mesial and distal to upper central
incisors and space opened for implant between upper right first and second premolars. B. Upper central
incisor contact points built up with composite to balance smile; dental implant inserted in space between
upper right premolars. Canines were extruded, and first premolars in canine positions intruded, to produce
optimal gingival margins.
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JCO/SEPTEMBER 2010
A
A
Fig. 9 Case 2. A. Patient two years after appliance removal, with porcelain crown placed on implant in upper right first premolar position. Final
occlusion involved three premolars in upper right quadrant, with first
premolar replacing canine, and Class II molar relationship on left side.
Due to missing lower left first molar, lower midline was slightly deviated
to left and lower archform somewhat asymmetrical, requiring restoration to make maxillary left canine larger than right canine. Although no
maxillary retainer was bonded, upper space closure remained stable.
Patient’s smile was improved by enlarging central incisors, instead of
grinding canines, to match “new”, larger lateral incisors. B. 3mm overjet intentionally left after orthodontic treatment. C. Ideal overjet and
anterior occlusal guidance achieved after restoration of small upper
central incisors.
• Porcelain laminate veneers on the six anterior
teeth (following composite build-ups during ortho­
dontic treatment).
After 18 months of fixed-appliance treatment, the upper midline had been corrected, and
space had been opened between the upper right
premolars (Fig. 8A). Diastemas mesial and distal
to the central incisors were filled with composite
build-ups to make those teeth appear bigger and
thus balance the smile, and an osseointe­grated
implant was placed by Dr. Francesca Manfrini,
Riva del Garda, Italy (Fig. 8B).
Orthodontic finishing took 11 months; overall treatment time was 30 months. The final occlusion involved three maxillary premolars on the
right side and the first molars in a Class II relationship on the left side, with canines substituting for
the missing lateral incisors and first premolars
replacing the canines on both sides (Fig. 9A). The
marginal periodontal contours and smile line were
optimized by the premolar intrusion, canine extru-
VOLUME XLIV NUMBER 9
B
C
sion, and torque control.20-22 The upper canines
were slightly reshaped on the buccal and palatal
surfaces, but were not ground or reduced in volume. Although the alignment of the six upper
anterior crowns was ideal, a 3mm overjet persisted
palatal to the upper central incisors (Fig. 9B); this
was later filled by restorations (Fig. 9C).
The cosmetic phase, performed by Dr.
Giovanni Manfrini, Riva del Garda, Italy, began
during treatment with build-ups on the central
incisors and continued with composite build-ups
on the “new” lateral incisors and canines a few
days before debonding. In the 10 months after
orthodontic treatment, stabilization was achieved
by occlusal equilibration. A porcelain crown was
placed on the implant, while the upper six anterior
teeth were restored with porcelain laminate veneers
(Fig. 9A). The macroesthetic elements of the smile
were in better balance than before treatment, primarily because the canines were not reduced to
substitute for the lateral incisors, but the central
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The Space-Closure Alternative for Missing Maxillary Lateral Incisors
incisors were enlarged to match the “new” lateral
incisors. This solution is often the best strategy in
lateral agenesis cases, in which the central incisors
tend to be small.23
A mandibular six-unit lingual retainer was
bonded; in the upper arch, an Essix* retainer was
used for six months after occlusal equilibration.
Two years after maxillary retention, there was no
tendency for space reopening, probably because of
the occlusal equilibration with no CO/CR discrepancy and with lateral working excursions of the
lateral incisors, canines, and first premolars.
Discussion
These and previous case reports have demonstrated that by using a combination of carefully
performed orthodontic space closure and cosmetic build-ups of several teeth with either composite resin or porcelain laminate veneers, it is
possible to treat patients with one or both missing
maxillary lateral incisors and a coexisting malocclusion to a result that provides the look of a
healthy, natural dentition.20,21
A major advantage of such an approach is the
permanence of the finished result. The alveolar
bone height is maintained by early mesial movement of the canine, and the need for removable or
resin-bonded retainers until the implant insertion
is avoided. At the end of orthodontic treatment,
porcelain veneers can be placed directly on any of
the anterior teeth, because the two common reasons for postponing permanent restorations in
young and adolescent patients—risk of pulp perforation and exposure of gingival crown margins
during tooth eruption—are not contraindications
for the minimally invasive preparations with
enamel-bonded porcelain.24,25 The tendency of the
spaces to reopen after treatment can be overcome
with properly finished occlusal contacts and longterm retention. A bonded retainer should be supplemented with a removable plate to be worn
continuously for six months and then at night. No
apparent side effects were noticed from this regimen in a 10-year follow-up study.26
*Dentsply Raintree Essix, 6448 Parkland Drive, Sarasota, FL
34243; www.essix.com.
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With the space-closure alternative, the
healthy gingival tissues and intact interdental gingival papillae will mature in synchrony with the
patient’s own teeth, so that long-term modifications will appear naturally (Fig. 2). This is in
contrast to long-term experiences with singleimplant crowns in the esthetic zone.9,10,13 In an
award-winning article describing 10-year followups of oral implants, Thilander and colleagues
found increasing degrees of infraocclusion even
after completion of growth, and significant marginal bone loss at tooth surfaces adjacent to the
implants.9 Marked infraocclusion of single-implant
crowns in mature adults was also reported by
Bernard and colleagues10 and by Jemt.13 Our conclusion is that lateral incisor agenesis in patients
with gummy smiles should be treated with space
closure. If the treatment plan must include space
reopening, it is preferable to open the spaces posteriorly and insert implants in the premolar areas11
(Figs. 7,8).
Our experience with currently available
materials for composite build-ups has been unsatisfactory, since such restorations need frequent
maintenance and renewal. Except for composite
“corners” on canines in lateral incisor positions,
we therefore prefer to use the more durable porcelain veneers.24,25 If desired, these can be made after
a retention period and after functional occlusal
adjustments by selective grinding. Porcelain
veneers on the canines and first premolars,20,21 as
well as on the central incisors if these need to be
widened or elongated,16,23 are more expensive for
the patient than grinding and build-ups, but their
cost compares favorably with that of restorations
on single-tooth implants. Long-term maintenance
of composite resin build-ups can also be expensive.
The porcelain veneers have shown excellent longterm durability and esthetics, even when the gingival margin retracts with time. Light reflection
appears normal, in contrast to ceramic crowns and
porcelain-fused-to-gold teeth, where the shadowing effect of the incoming light results in a dark
background.24
Agenesis of lateral incisors in Class III malocclusions, especially with narrow maxillae and
pronounced spacing, has traditionally been regarded as an undebatable indication for space reopen-
JCO/SEPTEMBER 2010
Rosa and Zachrisson
ing and prosthetic rehabilitation. It is held that the
reopening of spaces facilitates expansion of the
maxillary arch and provides dentoalveolar compensation, significantly improving the profile. The
Class III case shown here (Figs. 3,4), like similar
cases described previously,21,27 demonstrates that
space closure can be a valid alternative. The
changes in the face and profile are more correlated to modifications made in the vertical dimension than to sagittal changes at the incisor level. It
is remarkable that in the patient shown here, even
after a 7mm retraction of the upper incisors with
a resulting anterior crossbite, there was no noticeable profile change. Recent developments in mini­
screws may facilitate anchorage in such cases.
Class III patients with missing lateral incisors are
obviously difficult to treat, and good compliance
is mandatory, but long-term stability can still be
achieved without negative side effects on the face
and profile.
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